The directive rightly points out that those from backgrounds most affected by HIV are also the most marginalized. They are the same populations that are most affected by criminal law enforcement. So any measure that public authorities may take that disproportionally affects those who are more affected by HIV will have an adverse effect on the prevention of the disease. I could give you many examples: the criminalization of sex work or drug use, in which people are stigmatized more and in which their access to prevention and treatment services is negatively affected.
More broadly, public authorities have a major presence in the lives of marginalized people living with HIV. That often means that they find that their care is interrupted, that they are incarcerated or in court. They may also live a precarious existence that can have a negative impact on their relationship with their treatment team, their consistency of treatment and their ability to take the precautions necessary to prevent HIV.
Any activity that leads to those vulnerable to HIV being over-exposed to the court system will, without doubt, have a negative impact on public health efforts in prevention.